ConnectionOptions interface is incompatible with @types/pg definitions

[jameshfisher]

Using pg-connection-string with @types/pg currently results in a type error like this:

Argument of type 'ConnectionOptions' is not assignable to parameter of type 'PoolConfig'.
  Types of property 'database' are incompatible.
    Type 'string | null | undefined' is not assignable to type 'string | undefined'.
      Type 'null' is not assignable to type 'string | undefined'.ts(2345)

See clashing definition: https://github.com/DefinitelyTyped/DefinitelyTyped/blob/08f0feedca9329fe95d23ccc64886e3db03195bf/types/pg/index.d.ts#L18

[hjr3]

There are more problems with having ConnectionOptions match ClientConfig. See #2280

We landed #3128 to remedy this issue. Please let me know if you are still having problems.